1. Field of the Invention
This invention relates to the correction of keyboard input text as stored for display or hard copy printing, and more particularly, to the selection from among multiple keyboard character sets for correct matching.
2. Description of Prior Art
Prior art relating to the present invention includes:
(a) Key-to-display systems such as IBM OS/6 System in which an 8-bit extension of the 7-bit magnetic card code was utilized wherein a keyboard number for a document was saved in a document master format and was made operator-selectable. For multi-line portions of the document, where another keyboard character set was required, provision was made for a change of the keyboard and a format change. One problem with the OS/6 System was that an operator had to either find and inspect the prior format or had to remember the identification of the active input keyboard in order to know what key to press for inclusion in the text of a given desired graphic.
Further, the 6-byte sequences utilized in the OS/6 made for an inefficient use of storage for words or phrases, especially in limited areas such as margin text.
Further, if the operator changed the keyboard specified in the master format or in a format change, the printed/displayed text would also change, since the internal code points were not retranslated. The same result would take place if a block of text were moved to a section of the document keyed under a different format.
(b) The IBM 5520 System eliminated some of the above problems attendant the OS/6 System by adopting specific EBCDIC codes as its internal text representation. This required each point to be self-defining. Thus, keyboarding was strictly an input function and the data steam was independent of the active input keyboard. At any time, the operator could change the input keyboard without affecting the existing text. However, the IBM 5520 approach involved difficulty in communicating with other devices such as the OS/6 System.